Life raft



1967 E. R. VORENKAMP 3,332,094

LIFE RAFT Filed May 11, 1965 2 Sheets-Sheet 1 INVENTOR 1?? VJQWKAWP VATTORNEYS July 25, W? E. Fi. VORENKAMP Z LIFE RAFT Filed May 11, 1965 2Sheets-Sheet 2 Z5 224 FA W INVENTOR 33627 gf/affwmnp ATTORNEYS UnitedStates Patent 3,332,094 LIFE RAFT Egbert Roeloi Vorenkamp, New Orleans,La., assignor to Salerco, Inc., Orleans Parish, La., a corporation ofLouisiana Filed May 11, 1965, Ser. No. 454,784

19 Claims. (Cl. 9-11) This invention relates to a novel life raft, andmore particularly, to a life raft which is substantially completelyflexible.

Heretofore, life-saving rafts are made of rigid or semirigidconstruction. The prior art rafts generally obtain their buoyancy by thedisplacement of a volume of water corresponding to the volume enclosedby the outside surfaces of the rafts. That is to say, the prior artrafts would lose all or a substantial portion of their buoyancy ifpunctured. This can frequently happen around a sinking ship where fire,explosions and/0r debris are present.

Most of the existing life rafts also suffer from the disadvantage ofrequiring much space for storage purposes, thereby limiting the numberof crafts which can be carried aboard a vessel. Even in the case of airinflatable rubber rafts, it is frequently time-consuming to launch therafts, and difficult to board the rafts after launching because onecannot jump onto such rafts from a ships deck. The wooden life boatshave the further disadvantage of being partially inaccessible in an emergency-roughly one-half of the wooden life boats on a ship may be lostbecause the sinking ship is listing heavily on one side therebyrendering the life boats stored along the opposite side of the shipunlaunchable.

It is, therefore, an object of the present invention to provide a noveland improved life raft.

It is another object of the invention to provide a life raft which issubstantially completely flexible.

It is a further object of the invention to provide a life raft which iscompact in storage and yet has a large carrying capacity when launched.

Another object of the invention is to provide a life raft which is hightemperature resistant and whose carrying capacity is not affected bypunctures.

Still other objects will be apparent from the following description andclaims in conjunction with the accompanying drawings, which illustratedifferent embodiments of the invention and in which:

FIGURE 1 is a plan view partly in section of one embodiment of the liferaft of the present invention;

FIGURE 2 is an elevational view in section taken along line 2-2 inFIGURE 1;

FIGURE 3 is a perspective view showing the details of a corner of thelife raft of FIGURE 1;

FIGURE 4 is a plan view of another embodiment of the life raft of thepresent invention;

FIGURE 5 is a side elevation view of the life raft of FIGURE 4; and

FIGURE 6 is a sectional elevation view taken along line 6-6 in FIGURE 4.

The above objects are obtained by making a life raft from asubstantially flat sheet of a cellular synthetic material, without anyrigid frame or stiffening members. The buoyancy of the raft results fromthe difference between the densities of the water and that of thecellular synthetic material.. 7

When a flat sheet of buoyant material is placed in rough water, onewould expect that part of the waves would go over the sheet and a partgo under the sheet. Unexpectedly, I have found that when a raft made ofa sheet of flexible material is placed in a wavy sea, the waves would gounder the raft and essentially no water would be washed onto the raft.Such a flexible raft would undulate in a vertical direction in wavywaters, and the 3,332,094 Patented July 25, 1957 presence of theflexible raft would calm the waves in much the same way as a layer ofoil commonly known as an oil slick would. In this respect, the flexibleraft of the present invention is much more stable in rough waters thanthe conventional rigid or semi-rigid rafts.

Although a flat sheet of a cellular synthetic material will serve wellas a life raft, I prefer to cover the flat surfaces of the flat sheetwith a network of a webbing material, such as nylon rope. This networkof ropes can serve as a rope ladder for departing personnel when thelife raft is draped over a side of a sinking ship. After the raft islaunched, the network of ropes will serve as handholds for steadyingpurposes. V The life raft of my invention can be made of any flexible,cellular synthetic materials. I have found flexible, expanded, andplasticized polyvinyl chloride closed-cell plastic sheets to beparticularly suitable. Such a sheet of foamed polyvinyl chloride may beobtained, for example, from the U8. Rubber Company under its trade nameEnsolite which has a density of 3.5 to 5 lbs./ft. and water absorptionof about 1 lb. of water per cubic foot. Such foamed polyvinyl chloridehas excellent thermal insulating quality, tensile strength and shockabsorbing property. It is also fire resistant. Another example ofsuitable foamed material is foamed plasticized polyvinyl chloride inwhich there are 40 parts of dioctyl phthalate to 60 parts of polyvinylchloride having a density of 4 lbs/cu. ft.

In one embodiment of the present invention, I increase the tensilestrength of the foamed polyvinyl chloride by bonding two sheets of thefoamed material together with any suitable adhesive, such as glue, andplacing a number of webs or strips of a flexible material having hightensile strength thereinbetween. For this purpose, I prefer to use anumber of rubber impregnated nylon webs or straps which, of course, areflexible. The embedded nylon webs can be made to extend beyond theperimeter of the sheets of foamed polyvinyl chloride and be used tosecure the network of ropes on both surfaces of the raft in place.Alternatively, the network of ropes may be secured directly, to the raftby threading through eyelets or grommets located at the perimeter of theraft.

In the above discussion, it should be understood that the network ofrope covering the outside surfaces of the raft is in addition to andseparate from the embedded webs, although they may be made ofessentially the same material.

In another embodiment of my invention, a single layer of foamed andplasticized polyvinyl chloride is completely enclosed in a syntheticsheeting material. I prefer to use, as the synthetic sheeting material,a synthetic rubber impregnated nylon cloth which is impermeable towater. The synthetic rubber is preferably one having high tensilestrength, tough and high temperature resistant. A suitable syntheticrubber for impregnating the nylon cloth is a butadiene-acrylonitrilepolymer containing carbon black which has high tensile strength and canwithstand extreme cold and high heat. An example of such butadiene-acrylonitrile polymer is Herecrol, sold by the Heresite & ChemicalCo. The layer of foamed polyvinyl chloride may be encased in the nyloncloth impregnated with the butadiene-acrylonitrile rubber as follows:

Cover each of the flat surfaces of the layer of polyvinyl chloride witha sheet of the impregnated nylon cloth. The sheets should have slightlylarger areas than a the layer so as to provide a margin for gluing thesheets together. The sheets may be glued together at the margins by theuse of uncured butadiene-acrylonitn'le polymer and then curing thepolymer to convert the sheets into a sealed bag. The layer of encasedpolyvinyl chloride may also be bonded to the inside surfaces of thesheets by gluing with the same uncured butadiene-acrylonitrile polymer.

In the case of the last-mentioned embodiment, the sheets ofbutadiene-acrylonitrile can be made to extend substantially beyond theperiphery of the layer of polyvinyl chloride in at least one direction.This excess sheeting material may be rolled and secured to a side of theraft when not in use. When unrolled, this excess sheeting material fromtwo opposite sides of the raft can be secured together to form asemi-enclosed, arched or straight sided tent-like space by using severalwooden, metal or plastic laths (which can be stored in the rolled excesssheeting material, for example) as support. Because thebutadieneacrylonitrile polymer is high temperature-resistant, the excesssheeting material can serve as a fire wall when there is burning oil onthe sea after a shipwreck.

In any of the embodiments, a grab line may be formed by securing a ropearound and slightly beyond the periphery of the raft. This grab line canbe secured, for example, to the ends of the embedded webs. The purposeof the grab line is, of course, to allow swimmers to hold onto the raftbefore being rescued.

The life raft of the present invention can be launched by simplydropping the same into the water. No matter which side of the raft isturned up, the raft will be ready for use, an advantage not found inother life rafts or boats.

Since the life raft of the present invention is made of flexible andresilient material having excellent shockabsorbing properties, after theraft is thrown overboard, the persons leaving a sinking ship may get onthe raft by simply jumping onto it.

A number of harness clips may be attached to the grab line for lashingseveral life rafts together thereby forming a floating island. Asidefrom possible increased stability due to increased size, the floatingisland will also keep the survivors together for easier rescue. Therescue operation is further assisted by the fact that a life raftaccording to the present invention sits low on the water and so is notsubjected to as much drifting as conventional rafts.

When the rafts of the present invention are not in use, they can beeasily stored by rolling into cylindrical form. Because the cellularsynthetic materials used to make the rafts are usually good insulatingmaterials, the rafts, with or without a slight modification in theirconstruction, can be used as the insulating material on the carryingvessel. Thus, parallel and flexible steel strips may be substituted forthe webs embedded in the polyvinyl chloride layer. These rafts withembedded flexible steel strips can be arched across the ceiling of anairplane, for example, and serve as the insulating material until anaccident occurs.

The parallel and flexible steel strips embedded in the plasticizedpolyvinyl chloride layer will impart great strength to the life raftwithout substantially affecting its flexibility. Such a raft can be usedfor transporting heavy equipment and be towed by fitting the steelstrips with clips or hooks. A propelling device, such as a marineengine, can be mounted on such a raft. The mounting of a propeller typemotor, for example, can be accomplished by cutting a rectangular slot inthe raft near the leading edge of the raft, and mounting a supportingframe for the motor (made of wooden beams or metallic bars) around theslot.

The steel strip-reinforced raft can also be used as a floating platformfor transferring people and equipment between a boat and a drillingplatform located in the open sea. One of the problems of transferringpeople and equipment to and from a platform (such as one of theso-called Texas Towers) is the fact that the waves tend to smash a smallboat against the frame of the platform and frequently people are caughtin between and injured. When the raft is used as a platform, a smallboat can run onto the raft and a part of the boat would be 4 above theraft. In this way, the boat would be flexibly grounded on the raft andpersonnel can jump from the boat onto the raft or vice versa. Becausethe raft is fiexible and resilient, even if a person is caught betweenthe raft and a rigid frame, the resulting injury, if any, would beminor.

In FIGURE 1, a life raft 11 is shown which is made of a substantiallyflat sheet of a flexible and cellular polyvinyl chloride. A network ofnylon ropes 12 covers the life raft. The ropes 12 are knotted atintersections 13 to keep them in place. The ropes 12 are attached to theinternal network of webs 14 which extend beyond the edges of the raft(more clearly shown in FIGURE 3). A grab line 15, which is also made ofnylon rope, is attached to the ends of the webs 14 and surrounds thelife raft 11 circumferentially. Attached to the grab line 15 are anumber of harness clips 16 which may be used to lash several life raftstogether.

In FIGURE 2, the life raft '11 is shown to be made of two layers offoamed and plasticized polyvinyl chloride 17. Sandwiched between the twolayers of polyvinyl chloride are the webs 14. The nylon webs 14 aresomewhat longer than the life raft and the ends of each web are exposed.There are two grommets or eyelets 18 and 19 located at each of theexposed ends of webs 14. Grommets 19 are used for threading the ropes 12and grommets 18 are used for threading the gra-b line 15.

In FIGURE 3, a corner of the life raft of FIGURE 1 is shown in detail. Asuitable harness clip 16 is also shown. A cementing material 27 is shownbetween the two layers of foamed polyvinyl chloride.

In FIGURE 4, another embodiment of the present invention is shown aslife raft 20. In this embodiment a single sheet of foamed andplasticized polyvinyl chloride 21 is covered with a high temperatureresistant sheeting material 22. The sheeting material 22 is made largerthan the raft and the excess on one side is rolled into a roll 23 andsecured to that side of the raft by tying strings 24. The excess on theother side is normally rolled and tied up, too, but is shown stretchedout. This embodiment of the raft also has a network of ropes 25 coveringthe surfaces of the raft. Ropes 25, in contrast to ropes 12 of FIGURE 1,are attached to the life raft through grommets 26 located at the edgesof sheeting material 22.

In FIGURE 5, the life raft of FIGURE 4 is shown in an elevation view,with the right end of the excess sheeting material 22 being shown insolid line in a stretched out position and in dash line in an uprightposition for use as a fire wall or weather shield. Flexible wooden lathsor metal or plastic strips (not shown) may be stored in roll 23 or underand over ropes 25 without reducing the flexibility of the raftsignificantly for use in making an arched or straight sided, one-endedtent like structure. The strips would be used to hold the side excessesupright and they may be tied at their apex juncture. The lower end ofthe strips may rest against the corners between the bottom and sideexcesses.

The construction of the life raft of FIGURE 4 is shown in detail inFIGURE 6. The flexible and foamed sheet of polyvinyl chloride 21 isshown cemented to the high temperature resistant sheeting material 22.

The invention will now be more particularly described by the followingexamples:

Example 1 A life raft having a surface area 9' x 14 was made with foamedand plasticized polyvinyl chloride 4" thick. This raft was covered witha sheeting material on both sides. The sheeting material is essentiallya nylon cloth impregnated with butadiene-acrylonitrile synthetic rubbercoating. Two sheets of the sheeting material were used, each about 20' x16 in size. The layer of foamed polyvinyl chloride was placed betweenthe two sheets with the 14' edge of the polyvinyl chloride layerparallel to the 16' edge of the sheeting material. In this fashion,about 6 of excess sheeting material appear on each side of the liferaft. The outside surfaces of the raft were covered with a network ofnylon ropes. This raft was found to have a buoyancy of about 1200 lbs.,that is to say, it will support a load of about 1200 lbs. withoutsinking.

Example 2 A life raft was made by cementing two layers of foamedpolyvinyl chloride together. Each of said layers is 20' x 14' in areaand 2" thick. Sandwiched between the two layers is a network of nylonwebs in an arrangement substantially as shown in FIGURE 1. The outsidesurfaces of this raft were coated with a coating ofbutadiene-acrylonitrile synthetic rubber. A network of nylon ropescovered the outside surfaces of this raft, these ropes are secured inposition by knotting at intersections and attached to the ends of thewebs through eyelets. A grab line made of nylon rope was attachedcircumferentially around the raft at the ends of the webs.

This life raft was found to be extremely stable in open waters. The raftundulated 'with the waves and substantially no water was thrown onto theraft by the waves. Furthermore, the raft has a dampening effect on thewaves similar to that of an oil slick. Thus, when the waves have passedthe life raft, their magnitude is reduced and relatively calmer wavesfollowed the raft. This raft was found to be capable of supporting about5300 lbs.

The invention has been described with reference to the preferredembodiments thereof, but it will be understood that variations andmodifications can be effected within the spirit andscope of theinvention as defined by the following claims.

What is claimed is: 1. A life raft comprising: a continuous andsubstantially completely flexible planar layer made from a cellularsynthetic material having a density of between about 3.5 to 5 pounds perft.

and a network of ropes covering all surfaces of said planar layer, saidropes being attached to said planar layer at the periphery thereof. 2. Alife raft comprising: a continuous and substantially completely flexibleplanar layer made from a cellular synthetic material having a density ofbetween about 3.5 to 5 pounds per ft.

a waterproof and high temperature-resistant synthetic sheeting materialcompletely encasing said planar layer, and

a network of ropes covering all outside surfaces of said sheetingmaterial,

said ropes being attached to said sheeting material at the peripherythereof.

3. -A life raft comprising:

a continuous and substantially completely flexible planar layercomprising:

two sheets of a cellular synthetic material having a density of betweenabout 3.5 to 5 pounds per ft. bonded together and having a plurality ofwebbings embedded thereinbetween, and

a network of ropes covering all surfaces of said planar layer, saidropes being attached to said planar layer at the periphery thereof.

all. A life raft comprising:

a continuous and substantially completely flexible planar layercomprising:

two sheets of a cellular synthetic material having a density of betweenabout 3.5 to 5 pounds per ft. bonded together and having a plurality ofwebbings n embedded thereinbetween, said planar layer having awaterproof and high temperature-resistant synthetic material coatedthereon,

and a network of ropes covering all surfaces of said coated planarlayer, said ropes being attached to said coated planar layer at theperiphery thereof.

5. A life raft comprising:

a continuous and substantially completely flexible planar layercomprising:

two sheets of a cellular synthetic material having a density of betweenabout 3.5 to 5 pounds per ft. bonded together and having a plurality ofwebbings embedded thereinbetween,

a waterproof and high temperature-resistant, synthetic sheeting materialcompletely encasing said planar layer, and

a network of ropes covering all outside surfaces of said sheetingmaterial, said ropes being attached to said sheeting material at theperiphery thereof.

6. A life raft comprising:

a continuous and substantially completely flexible planar layercomprising:

two sheets of an expanded and plasticized polyvinyl chloride cellularplastic having a density of between about 3.5 to 5 pounds per ft. bondedtogether and having a plurality of rubber-impregnated nylon webbingsembedded between said two sheets, said embedded webbings extendingbeyond said two sheets,

a coating of a waterproof and high temperature-resistant syntheticrubber material completely covering the outside surfaces of said planarlayer,

and a net-work of rubber-impregnated nylon ropes covering all outsidesurfaces of said coated planar layer, said ropes being attached to saidembedded nylon webbing at a point beyond the perimeter of said coatedplanar layer.

7. A life raft according to claim 6 further comprising a nylon ropeattached to the ends of said embedded nylon webbings thereby forming agrab line circumferentially around said life raft.

' 8. A life raft according to claim 7 further comprising a plurality ofharness clips attached to said grab line for lashing a plurality of saidrafts together to form a large island.

9. A life raft comprising:

a continuous and substantially completely flexible planar layer made ofan expanded and plasticized polyvinyl chloride cellular plastic having adensity of between about 3.5 to 5 pounds per ftfi,

a waterproof and high temperature-resistant synthetic sheeting materialcompletely encasing said planar layer,

and a network of rubber-impregnated nylon ropes covering all outsidesurfaces of said sheeting material, said ropes being attached to saidsheeting material at the periphery thereof.

10. A life raft according to claim 9 further comprising arubber-impregnated nylon rope circumferentially attached to theperiphery of said sheeting material thereby forming a grab line.

11. A life raft according to claim 10 further compris ing a plurality ofharness clips attached to said grab line for lashing a plurality of saidrafts together to form a large island.

12. A life raft according to claim 9 wherein said sheeting materialextends substantially beyond said planar layer on at least one side ofsaid planar layer, for use as a shield.

13. A life raft according to claim 9 wherein said sheeting materialextends substantially beyond said planar layer on two opposite sides ofsaid planar layer to permit the excess sheeting materials to be formedinto a tent.

14. A life raft comprising:

acontinuous and substantially completely flexible planar layercomprising:

two sheets of an expanded and plasticized polyvinyl chloride cellularplastic having a density of between about 3.5 to 5 pounds per ft. bondedtogether and having a plurality of parallal and flexible metallic stripsembedded thereinbetween, said'metallic strips extending beyond said twosheets,

a coating of a waterproof and high temperature-resistant syntheticrubber material completely covering the outside surfaces of said planarlayer,

and a network of rubber-impregnated nylon ropes covering all surfaces ofsaid coated planar layer, said ropes being attached to said metallicstrips at points beyond the perimeter of said coated planar layer.

15. A life raft according to claim 14 further comprising arubber-impregnated nylon rope attached to the ends of said metallicstrips thereby forming a grab line circumferentially around said liferaft.

16. A raft according to claim 15 further comprising a plurality ofharness clips attached to said grab line for lashing a plurality of saidrafts together to form a large island.

17. A life raft comprising:

a continuous and substantially completely flexible planar layer made ofan expanded closed cell cellular plastic material having a density of3.5 to 5 lbs/ft. and said layer being approximately 2 to 4 inches thick,

and a network of ropes covering all surfaces of said References CitedUNITED STATES PATENTS 1/1858 Taggart 911 11/1953 Hoffman 98 11/1964Shewmake et al. 9-l1 FOREIGN PATENTS 2/ 1946 Australia. 8/1963 Canada.8/1955 Great Britain. 2/ 1959 Great Britain.

20 MILTON BUCHLER, Primary Examiner.

T. MAJOR, Assistant Examiner.

1. A LIFE RAFT COMPRISING: A CONTINUOUS AND SUBSTANTIALLY COMPLETELYFLEXIBLE PLANAR LAYER MADE FROM A CELLULAR SYNTHETIC MATERIAL HAVING ADENSITY OF BETWEEN ABOUT 3.5 TO 5 POUNDS PER FT.**3, AND A NETWORK OFROPES COVERING ALL SURFACES OF SAID PLANAR LAYER, SAID ROPES BEINGATTACHED TO SAID PLANAR LAYER AT THE PERIPHERY THEREOF.